/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "tool/plinko/lib/cons.h"
#include "tool/plinko/lib/plinko.h"

static inline int Probe(unsigned h, unsigned p) {
  return (h + p * p) & MASK(TERM);
}

static inline int Hash(unsigned h, unsigned x) {
  return MAX(2, ((h * 0xdeaadead) ^ x) & MASK(TERM));
}

static int Interner(dword t, int h, int p) {
  dword u;
  if ((u = Get(h))) {
    if (u != t) {
      h = Interner(t, Probe(h, p), p + 1);
    }
    return h;
  } else if (++cAtoms < TERM / 2) {
    Set(h, t);
    SetShadow(h, DF(DispatchLookup));
    return h;
  } else {
    Error("too many atoms");
  }
}

int Intern(int x, int y) {
  return Interner(MAKE(x, y), (ax = Hash(x, ax)), 1);
}
